My brand new q6600 with the retail intel heatsinkfan combo runs my hottest core at about 43 idle but ive got a mid tower case with a lot of hard drives and a hot running video card too. i wouldnt be too worried about the temps youre getting, they can handle operating even at the 60 range but of course it is not good if they idle that high. your idle is a little higher than normal and the cause of it most often is a bunch of dust accumulated in the heatsink and on the fan. just pop your case open and spray compressed air in a can at the fan and heatsink without taking em out if you dont feel that comfortable and thatll do it. you can find the compressed air at your local electronics stores and walmart, etc. see if that helps, it cant hurt.
You are going to need to get a new heatsink & fan (HSF) if you want to get those temps right down (dont worry its a very simple to do .
I recommend getting a Xigmatek HDT-S1283 (And maybe a bolt through retention bracket but this is optional but will be worth it in the long run). Make sure you clean the top of your cpu with alcohol before apply new thermal paste. All up It should cost around $50
Try getting a ruler/tape measure and measure from the base of the HSF to where the side panel is & also measure the free space around it. It should be fine but if their not enough room for breathing room .etc their are good alternatives but that Xigmatek Is pretty much the best cooler you can get for the price.